Altering the Texture of Polymers on Demand

How to permanently etch patterns into polymer surfaces has been known for a while, but now engineers at Duke University have figured out for the first time how to add and remove patterns from large and curved areas of soft plastics and polymers, according to a press release from the university.

Reported in a journal article, the new process is called dynamic electrostatic lithography. “By changing the voltage applied to the polymer, we can alter the surface from bumpy to smooth and back again,” explained Xuanhe Zhao, who is team leader and an assistant professor of mechanical engineering and materials science at Duke, in a statement.

More specifically, a variety of patterns, including dots, segments, lines, and circles, can be made within milliseconds at sizes from millimeter to submicrometer, said Qiming Wang, a student in Zhao’s laboratory and the first author of the journal article, in a statement.

The new process could be useful for altering surface patterns on microfluidic chips.

So when would one need a reversible pattern? The researchers described potential applications of their method, such as creating surfaces that are self-cleaning and water-repellent, or even as platforms for controlled-release drug-eluting devices.

Theoretically, they could make rubber gloves with fingerprints that could be changed on demand. (Think more like grips on climbing gloves, but don’t rule out the spy possibilities.) Changing surface patterns could also be useful for microfluidic and camouflage technologies.

Zhao’s team developed the process after learning about how insulation on wires can develop creases and craters, and can fail after repeated exposure to voltage.

Siegfried Bauer, soft matter physics chair at the Johannes Kepler University in Linz, Austria, praised the work in a statement:

This is beautiful basic research with a huge potential for applications, a new technology platform is developed that allows the generation of dynamical patterns on large areas simply by the application of electrical voltages.

Source: “Process Makes Polymers Truly Plastic,” Duke University press release, 3/15/12
Source: “Dynamic Electrostatic Lithography: Multiscale On-Demand Patterning on Large-Area Curved Surfaces,” Advanced Materials, 3/15/12
Image from Wikimedia Commons, used under Fair Use: Reporting.

Rachel Petkewich is a freelance science writer and editor. She has worked as a research scientist in the chemical industry and spent eight years as a staff writer and editor at various science journals and magazines, including Chemical & Engineering News.

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